Accumulation of Arachidonic Acid Cyclo‐ and Lipoxygenase Products in Rat Brain During Ischemia and Reperfusion: Effects of Treatment with GM1‐Lactone

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Abstract
The aim of our study was to investigate the changes of various biochemical parameters (concentrations of lactate, free arachidonate, cyclo‐ and lipoxygenase products) in rat brain after ischemia and reperfusion and the effects of pre‐treatment with the ganglioside derivative GM1‐lactone on the same parameters. Ischemia was induced by reversible occlusion of common carotid arteries for 20 min, which in‐cluded a final 5 min of respiration of 5% oxygen in nitrogen. Reperfusion was obtained by removing the occlusion. Pre‐ischemic conditions were obtained on sham‐operated animals. Animals were killed by microwave irradiation of their heads. Brain levels of lactate and of free arachidonate were markedly increased after ischemia and returned to normal values at 5 min of reperfusion. Levels of the cyclooxygenase metabolites prostaglandin F2α, 6‐keto‐prostaglandin F1α, and thromboxane B2 were increased after ischemia, whereas levels of the lipoxygenase metabolite leukotriene C, (LTC4) did not. change. After reperfusion, a very' marked increase of the cyclooxygenase products occurred but not of LTC4. Treatment with GM1‐lactone prevented the elevation of cyclo‐ and lipoxygenase metabolites especially during reperfusion, with limited effects on lactate and free arachidonate levels.